Fluorescence Properties and Singlet Oxygen Quantum Yield of Parietin, an Anthraquinone Derivative Isolated from Teleoschistes Flavicans .

L.R. COMINI ; F.E. MORAN VIEYRA; R.A. MIGNONE; S.C. NÚÑEZ MONTOYA, ; MARIONI J ; J..L. CABRERA ; C.D. BORSARELLI.

Córdoba

Congreso; 16th INTERNACIONAL CONGRESS OF PHOTOBIOLOGY; 2014

Since several years anthraquinone (AQs) derivatives have been thoroughly studied in relation to their photosensitizing properties in photodynamic reactions [1,2]. On the basis of this, some of them showed good antibacterial and antiviral effects, by photosensitization of reactive oxygen species (ROS) such as superoxide anion (O2 .¯), hydroxyl radical (OH.) and singlet molecular oxygen (1O2), with subsequent oxidative damage [3, 4]. This time we report the purification and identification of parietin (PTN), an AQ isolated from vegetal specie: Teleoschistes flavicans (SW) Norm. (Telochistaceae). In addition, the spectroscopic properties of the pigment in CHCl3 as solvent, indicate that PTN absorbs blue light and shows almost 3% of fluorescence efficiency with a remarkable Stokes shift of 70 nm and non-exponential fluorescence decay, suggesting a possible excited-state tautomeric keto-enol or charge-transfer intramolecular equilibrium. The main results are summarized as follows. Additionally, we performed time-resolved detection of singlet oxygen luminescence at 1270 nm by 355 nm laser pulsed excitation (7 ns fwhm) and by using phenalen-1-one as reference compound the singlet molecular oxygen quantum yield. F  0.8 was determined, indicating that this AQs derivative shows good photosensitizing properties, which can be associated with its potential photodynamic activity . References [1] I. Gutiérrez, S.G. Bertolotti, M.A. Biasutti, A.T. Soltermann, N.A. García. Can. J. Chem. 1997, 75, 423. [2] K. Gollnick, S. Held, D.O. Mártire, S.E. Braslavsky. J. Photochem. Photobiol. A: Chem. 1992, 69, 155. [3] K. Zerdin, M.A. Horsham, R. Durham, P. Wormell, A.D. Scully. Reac.Funct.Polymers.2009, 69, 821. [4] Z. Luksiené. Food Technol. Biotechnol.2005, 43, 411.